Hi Laurent, Thank your your review. On 10/11/2012 11:49 PM, Laurent Pinchart wrote: > Hi Tomasz, > > Thanks for the patch. > > On Wednesday 10 October 2012 16:46:40 Tomasz Stanislawski wrote: >> This patch adds taking reference to the device for MMAP buffers. >> >> Such buffers, may be exported using DMABUF mechanism. If the driver that >> created a queue is unloaded then the queue is released, the device might be >> released too. However, buffers cannot be released if they are referenced by >> DMABUF descriptor(s). The device pointer kept in a buffer must be valid for >> the whole buffer's lifetime. Therefore MMAP buffers should take a reference >> to the device to avoid risk of dangling pointers. >> >> Signed-off-by: Tomasz Stanislawski <t.stanislaws@xxxxxxxxxxx> >> Acked-by: Hans Verkuil <hans.verkuil@xxxxxxxxx> > > Acked-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > > But two small comments below. > >> --- >> drivers/media/v4l2-core/videobuf2-dma-contig.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c >> b/drivers/media/v4l2-core/videobuf2-dma-contig.c index b138b5c..2d661fd >> 100644 >> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c >> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c >> @@ -148,6 +148,7 @@ static void vb2_dc_put(void *buf_priv) >> kfree(buf->sgt_base); >> } >> dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr); >> + put_device(buf->dev); >> kfree(buf); >> } >> >> @@ -168,6 +169,9 @@ static void *vb2_dc_alloc(void *alloc_ctx, unsigned long >> size) return ERR_PTR(-ENOMEM); >> } >> >> + /* prevent the device from release while the buffer is exported */ > > s/prevent/Prevent/ ? > s/release/being released/ ? >> + get_device(dev); >> + >> buf->dev = dev; > > What about just > > buf->dev = get_device(dev); > Right, sorry I missed that from your previous review :). Regards, Tomasz Stanislawski >> buf->size = size; -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
